Polymerization of vinylidene fluoride to waxy products



Patented Apr. 14, 1953 POLYMER-IZATION OF VINYLIDENE FLUO- RIDE TO WAXYPRODUCTS Charles B. Miller, Lynbrook, N. Y., and John D. Calfee, Dayton,Ohio, assignors to Allied Chemical & Dye Corporation, New York, N. Y., acorporation of New York No Drawing. Application November 13, 1950,Serial No. 195,474

(01. zoo-92.1)

3 Claims.

This invention relates to novel polymers of substantially outlasting thepreviously commerfluorine-containing, unsaturated compounds and,

to a process for the manufacture of such products. More particularly thepresent invention is directed to a novel process for the preparation ofpolymers of vinylidene fluoride.

This application is a continuation-in-part of our application Serial No.21,566, filed April 16, 1948.

In the past it has been proposed to polymerize vinylidene fluoride bycontacting the vinylidene fluoride at a temperature between 20 C'. and

250 C. under a pressure above 30 atmospheres with a polymerizationcatalyst. This process produces polymers of vinylidene fluoride inpowdery or granular form.

In accordance with this invention vinylidene fluoride is heated undersubstantially non-catalytic conditions at a temperature between 300 C.and 500 0., preferably between 400 C. and 450 C., and at an absolutepressure of at least 2,000 pounds per square inch, preferably between5,000 pounds per square inch and 10,000 pounds per square inch.

We have found that by polymerizing vinylidene fluoride under thespecified conditions of temperature and pressure in the substantialabsence of a catalyst, polymers varying from a mixture of a viscousliquid and a soft wax, having the physical properties of the softparaffin waxes,

to a hard wax, having the physical properties of the carnauba waxes, areobtainable. waxy polymers have good light and heat stability andcompared to the ordinary petroleum waxes are distinguished by their highwater-repellency, their resistance to inorganic acids and bases, and,particularly in the case of the harder Waxes, by their insolubility inpetroleum hydrocarbon and halogenated hydrocarbon solvents.

The waxy vinylidene fluoride polymers of this invention have been foundto be excellent for use in automobile and leather polishes, whereverresistance to petroleum hydrocarbon solvents such as gasoline and motoroils is an important consideration. The water-repellent properties ofthese new polymers also render them valuable for moisture-proofing paperand textiles and for coating metal to protect it against corrosion.

The solt waxes. of the invention have been found to provide superiorstop-cock lubrication.

These cially available greases. As such they may be used under a varietyof conditions, including high vacuum distillation. They are alsoespecially useful under conditions where solvents such as halogenatedhydrocarbons and petroleum hydrocarbons are handled, particularly inrefrigerator compressor service. Similarly, they are of value in nitricor mixed acid service, for example, as lubricants in pumps and packedglands.

The following example illustrates the method of carrying out of thepolymerization of this invention and the nature of the productsobtained:

A pressure-resistant stainless steel reaction vessel is purged of air bypassing deoxygenated nitrogen or other inert gas into the vessel untilessentially all oxygen is removed. The vessel is then closed, evacuatedand heated to reaction temperature. vinylidene fluoride containing lessthan P. P. M. and preferably less than 10 P. P. M. of oxygen is chargedto the vessel until reaction pressure is attained. The vessel is thenmaintained at reaction temperature to effect the polymerization. Datafor a series of runs at various temperatures and pressures are presentedin the following table:

Temp., Pressure, Reqctlm Character of C. bs./sq. in. Eggs; Polymer 1 4252, 300 6 Mixture of viscous l1quid and soft wax.

2 425-430 5, 300 8. 5 Mixture of soft wax and hard wax.

4 400 6, 500 4 Hard wax.

molecular weight over 2000 may be dissolved in acetone to producefilm-forming solutions.

We claim: I

1. The process for preparing waxy vinylidene fluoride polymers whichcomprises heating vinylidene fluoride containing less than 10 parts permillion of oxygen and in the absence of a catalyst at a. temperaturebetween 400 C. and 500 C. under a pressure of at least 2000 pounds persquare inch.

2. The process for preparing waxy vinylidene fluoride polymers whichcomprises heating vinylidene fluoride containing less than 10 parts per4 million of oxygen and in the absence of a catalyst at a temperaturebetween 400 C. and 450 C. under a pressure between 5000 pounds persquare inch and 10,000 pounds per square inch. 3. A Waxy vinylidenefluoride polymer obtained by the process of claim 1.

CHARLES B. MILLER.

JOHN D. CALFEE.

References Cited inthe file of this patent FOREIGN PATENTS Number

1. THE PROCESS FOR PREPARING WAXY VINYLIDENE FLUORIDE POLYMERS WHICHCOMPRISES HEATING VINYLIDENE FLUORIDE CONTAINING LESS THAN 10 PARTS PERMILLION OF OXYGEN AND IN THE ABSENCE OF A CATALYST AT A TEMPERATUREBETWEEN 400* C. AND 500* C. UNDER A PRESSURE OF AT LEAST 2000 POUNDS PERSQUARE INCH.